The present invention relates to method and apparatus for the real-time computation of radar cross sections in a distributed multiple computing system.
Radar has found many uses since its invention nearly 100 years ago. It can be used for relatively simple tasks such as detecting an approaching airplane at an airport or more complex tasks such as imaging a planet's surface from orbit or even from another planet. As a matter of national defense; radar can also be used to detect and subsequently identify approaching targets such as planes and missiles.
Operationally, radar systems use a transmitter to generate and radiate a radar beam in a preferred direction. Known various technologies, mechanical and electronic, exist for steering the beam such that the beam can cover a defined area of the sky. Reflections of the radar signal from an object will be received by a receiver and processed to yield desired information, such as the discrimination between decoy and real targets.
Identification of an object of interest, as opposed to simple detection of the object's presence, can be a computer intensive activity. One known technique for identifying an object based upon the returned radar signal is known as the “shooting-and-bouncing-rays” (SBR) method. Elaboration on the methodology is unnecessary here. Information on SBR methodology can be found in numerous sources, including the original paper on the technique, “Shooting and Bouncing Rays: Calculating the RCS of an Arbitrarily Shaped Cavity,” IEEE Transactions on Antennas and Propagation, Vol. 37, No. 2, (February 1989). Suffice it to say for purposes of this application that this technique enables the calculation of the radar cross-section (RCS) of an object of interest, from which the object itself can be determined.
As noted, the calculation of the RCS using the SBR method is computer intensive, meaning, of course, that its usefulness in situations where an RCS must be determined rapidly can be limited. For example, where there exists a plurality of approaching objects, such as real and dummy missile warheads, it is critical that the real be discriminated from the dummy so that the appropriate defensive countermeasures can be undertaken. A real-time computation of RCS in such situations is desirable to enable the use appropriate and effective defensive countermeasures. Using ever-more powerful computer processors can aid in speeding up this discrimination, but not to the extent desired or necessary.
To further enhance the rapidity with which object discrimination is accomplished a distributed computing system can be used. Such systems take advantage of a plurality of processors and software that divides the calculation between the various-processors. The processors could be in individual personal computers interconnected over a local area network or could all be located within a single machine and appropriately connected.
Increasing the number of processors doing an RCS calculation will not necessarily increase the speed of such calculations, that is, the time to finally calculate the RCS, since the calculation can be slowed by an unequal distribution of the calculation workload between the processors. Thus, there exists a need for a method and apparatus for more equally distributing the workload between a plurality of processors performing RCS calculations.
The present invention, as well as its various features and advantages, will become evident to those skilled in the art when the following description of the invention is read in conjunction with the accompanying drawings as briefly described below and the appended claims. Throughout the drawings, like numerals refer to similar or identical parts.